ffc team mailing list archive

[kent-and@xxxxxxxxx]

> On 21 June 2010 23:16, Kent Andre <kent-and@xxxxxxxxx> wrote:
>>
>> Strange. I used dorsal to compile the dev versions of the various
>> packages. Dolfin, ffc, and sfc are only a few days old.
>>
>> But do you have any suggestions for how to optimize the FFC generated
>> code ? I have used quadrature here, tensor representation is not good
>> in this application.
>
> I had a look at the generated code from FFC and SyFi
> (which by the way is a real pain when PyDOLFIN is involved)
>
> and realised that your comparison is not fair.
> FFC uses the UFL algorithm estimate_total_polynomial_degree() to
> compute the quadrature_degree.
> SFC uses (in this case) the UFL algorithm estimate_quadrature_degree()
> which is less conservative.
>
> This results in FFC using 25 integration points to compute the
> integral while SFC just uses 3.
>
> If you use the option:
>
> parameters ["form_compiler"]["quadrature_degree"] = "2"
>
> the comparison is _more_ fair and the numbers are almost the same.
> SFC still uses 3 points, while FFC now uses 4 points which leads to my
> answer to your first question:
> "How should I optimize FFC?" :)
>
> https://blueprints.launchpad.net/ffc/+spec/simplex-quadrature
>
> Kristian
>

Thanks! I get results that are really close to each other now.

Kent